<?php // $Id: lib.php,v 1.98.2.49 2009/01/01 23:53:47 skodak Exp $

///////////////////////////////////////////////////////////////////////////
//																	   //
// NOTICE OF COPYRIGHT												   //
//																	   //
// Moodle - Modular Object-Oriented Dynamic Learning Environment		 //
//		  http://moodle.com											//
//																	   //
// Copyright (C) 1999 onwards Martin Dougiamas  http://dougiamas.com	 //
//																	   //
// This program is free software; you can redistribute it and/or modify  //
// it under the terms of the GNU General Public License as published by  //
// the Free Software Foundation; either version 2 of the License, or	 //
// (at your option) any later version.								   //
//																	   //
// This program is distributed in the hope that it will be useful,	   //
// but WITHOUT ANY WARRANTY; without even the implied warranty of		//
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the		 //
// GNU General Public License for more details:						  //
//																	   //
//		  http://www.gnu.org/copyleft/gpl.html						 //
//																	   //
///////////////////////////////////////////////////////////////////////////
/**
 * File in which the grader_report class is defined.
 * @package gradebook
 */

require_once($CFG->dirroot . '/grade/report/lib.php');
require_once($CFG->libdir.'/tablelib.php');

/**
 * Class providing an API for the grader report building and displaying.
 * @uses grade_report
 * @package gradebook
 */
class grade_report_grader extends grade_report {
	/**
	 * The final grades.
	 * @var array $grades
	 */
	var $grades;

	/**
	 * Array of errors for bulk grades updating.
	 * @var array $gradeserror
	 */
	var $gradeserror = array();

//// SQL-RELATED

	/**
	 * The id of the grade_item by which this report will be sorted.
	 * @var int $sortitemid
	 */
	var $sortitemid;

	/**
	 * Sortorder used in the SQL selections.
	 * @var int $sortorder
	 */
	var $sortorder;

	/**
	 * An SQL fragment affecting the search for users.
	 * @var string $userselect
	 */
	var $userselect;

	/**
	 * List of collapsed categories from user preference
	 * @var array $collapsed
	 */
	var $collapsed;

	/**
	 * A count of the rows, used for css classes.
	 * @var int $rowcount
	 */
	var $rowcount = 0;

	/**
	 * Capability check caching
	 * */
	var $canviewhidden;

	/**
	 * Constructor. Sets local copies of user preferences and initialises grade_tree.
	 * @param int $courseid
	 * @param object $gpr grade plugin return tracking object
	 * @param string $context
	 * @param int $page The current page being viewed (when report is paged)
	 * @param int $sortitemid The id of the grade_item by which to sort the table
	 */
	function grade_report_grader($courseid, $gpr, $context, $page=null, $sortitemid=null) {
		global $CFG;
		parent::grade_report($courseid, $gpr, $context, $page);

		$this->canviewhidden = has_capability('moodle/grade:viewhidden', get_context_instance(CONTEXT_COURSE, $this->course->id));

		// load collapsed settings for this report
		if ($collapsed = get_user_preferences('grade_report_grader_collapsed_categories')) {
			$this->collapsed = unserialize($collapsed);
		} else {
			$this->collapsed = array('aggregatesonly' => array(), 'gradesonly' => array());
		}

		if (empty($CFG->enableoutcomes)) {
			$nooutcomes = false;
		} else {
			$nooutcomes = get_user_preferences('grade_report_shownooutcomes');
		}

		// if user report preference set or site report setting set use it, otherwise use course or site setting
		$switch = $this->get_pref('aggregationposition');
		if ($switch == '') {
			$switch = grade_get_setting($this->courseid, 'aggregationposition', $CFG->grade_aggregationposition);
		}

		// Grab the grade_tree for this course
		$this->gtree = new grade_tree($this->courseid, true, $switch, $this->collapsed, $nooutcomes);

		$this->sortitemid = $sortitemid;

		// base url for sorting by first/last name
		$studentsperpage = $this->get_pref('studentsperpage');
		$perpage = '';
		$curpage = '';

		if (!empty($studentsperpage)) {
			$perpage = '&amp;perpage='.$studentsperpage;
			$curpage = '&amp;page='.$this->page;
		}
		$this->baseurl = 'index.php?id='.$this->courseid. $perpage.$curpage.'&amp;';

		$this->pbarurl = 'index.php?id='.$this->courseid.$perpage.'&amp;';

		// Setup groups if requested
		if ($this->get_pref('showgroups')) {
			$this->setup_groups();
		}

		$this->setup_sortitemid();
	}

	/**
	 * Processes the data sent by the form (grades and feedbacks).
	 * Caller is reposible for all access control checks
	 * @param array $data form submission (with magic quotes)
	 * @return array empty array if success, array of warnings if something fails.
	 */
	function process_data($data) {
		$warnings = array();

		// always initialize all arrays
		$queue = array();
		foreach ($data as $varname => $postedvalue) {

			$needsupdate = false;

			// skip, not a grade nor feedback
			if (strpos($varname, 'grade') === 0) {
				$data_type = 'grade';
			} else if (strpos($varname, 'feedback') === 0) {
				$data_type = 'feedback';
			} else {
				continue;
			}

			$gradeinfo = explode("_", $varname);
			$userid = clean_param($gradeinfo[1], PARAM_INT);
			$itemid = clean_param($gradeinfo[2], PARAM_INT);

			$oldvalue = $data->{'old'.$varname};

			// was change requested?
			if ($oldvalue == $postedvalue) { // string comparison
				continue;
			}

			if (!$grade_item = grade_item::fetch(array('id'=>$itemid, 'courseid'=>$this->courseid))) { // we must verify course id here!
				error('Incorrect grade item id');
			}

			// Pre-process grade
			if ($data_type == 'grade') {
				$feedback = false;
				$feedbackformat = false;
				if ($grade_item->gradetype == GRADE_TYPE_SCALE) {
					if ($postedvalue == -1) { // -1 means no grade
						$finalgrade = null;
					} else {
						$finalgrade = $postedvalue;
					}
				} else {
					$finalgrade = unformat_float($postedvalue);
				}

				$errorstr = '';
				// Warn if the grade is out of bounds.
				if (is_null($finalgrade)) {
					// ok
				} else if ($finalgrade < $grade_item->grademin) {
					$errorstr = 'lessthanmin';
				} else if ($finalgrade > $grade_item->grademax) {
					$errorstr = 'morethanmax';
				}
				if ($errorstr) {
					$user = get_record('user', 'id', $userid, '', '', '', '', 'id, firstname, lastname');
					$gradestr = new object();
					$gradestr->username = fullname($user);
					$gradestr->itemname = $grade_item->get_name();
					$warnings[] = get_string($errorstr, 'grades', $gradestr);
				}

			} else if ($data_type == 'feedback') {
				$finalgrade = false;
				$trimmed = trim($postedvalue);
				if (empty($trimmed)) {
					 $feedback = NULL;
				} else {
					 $feedback = stripslashes($postedvalue);
				}
			}

			$grade_item->update_final_grade($userid, $finalgrade, 'gradebook', $feedback, FORMAT_MOODLE);
		}

		return $warnings;
	}


	/**
	 * Setting the sort order, this depends on last state
	 * all this should be in the new table class that we might need to use
	 * for displaying grades.
	 */
	function setup_sortitemid() {

		global $SESSION;

		if ($this->sortitemid) {
			if (!isset($SESSION->gradeuserreport->sort)) {
				if ($this->sortitemid == 'firstname' || $this->sortitemid == 'lastname') {
					$this->sortorder = $SESSION->gradeuserreport->sort = 'ASC';
				} else {
					$this->sortorder = $SESSION->gradeuserreport->sort = 'DESC';
				}
			} else {
				// this is the first sort, i.e. by last name
				if (!isset($SESSION->gradeuserreport->sortitemid)) {
					if ($this->sortitemid == 'firstname' || $this->sortitemid == 'lastname') {
						$this->sortorder = $SESSION->gradeuserreport->sort = 'ASC';
					} else {
						$this->sortorder = $SESSION->gradeuserreport->sort = 'DESC';
					}
				} else if ($SESSION->gradeuserreport->sortitemid == $this->sortitemid) {
					// same as last sort
					if ($SESSION->gradeuserreport->sort == 'ASC') {
						$this->sortorder = $SESSION->gradeuserreport->sort = 'DESC';
					} else {
						$this->sortorder = $SESSION->gradeuserreport->sort = 'ASC';
					}
				} else {
					if ($this->sortitemid == 'firstname' || $this->sortitemid == 'lastname') {
						$this->sortorder = $SESSION->gradeuserreport->sort = 'ASC';
					} else {
						$this->sortorder = $SESSION->gradeuserreport->sort = 'DESC';
					}
				}
			}
			$SESSION->gradeuserreport->sortitemid = $this->sortitemid;
		} else {
			// not requesting sort, use last setting (for paging)

			if (isset($SESSION->gradeuserreport->sortitemid)) {
				$this->sortitemid = $SESSION->gradeuserreport->sortitemid;
			}else{
				$this->sortitemid = 'lastname';
			}

			if (isset($SESSION->gradeuserreport->sort)) {
				$this->sortorder = $SESSION->gradeuserreport->sort;
			} else {
				$this->sortorder = 'ASC';
			}
		}
	}

	/**
	 * pulls out the userids of the users to be display, and sorts them
	 */
	function load_users() {
		global $CFG;

		if (is_numeric($this->sortitemid)) {
			// the MAX() magic is required in order to please PG
			$sort = "MAX(g.finalgrade) $this->sortorder";

			$sql = "SELECT u.id, u.firstname, u.lastname, u.imagealt, u.picture, u.idnumber
					  FROM {$CFG->prefix}user u
						   JOIN {$CFG->prefix}role_assignments ra ON ra.userid = u.id
						   $this->groupsql
						   LEFT JOIN {$CFG->prefix}grade_grades g ON (g.userid = u.id AND g.itemid = $this->sortitemid)
					 WHERE ra.roleid in ($this->gradebookroles) AND u.deleted = 0
						   $this->groupwheresql
						   AND ra.contextid ".get_related_contexts_string($this->context)."
				  GROUP BY u.id, u.firstname, u.lastname, u.imagealt, u.picture, u.idnumber
				  ORDER BY $sort";

		} else {
			switch($this->sortitemid) {
				case 'lastname':
					$sort = "u.lastname $this->sortorder, u.firstname $this->sortorder"; break;
				case 'firstname':
					$sort = "u.firstname $this->sortorder, u.lastname $this->sortorder"; break;
				case 'idnumber':
				default:
					$sort = "u.idnumber $this->sortorder"; break;
			}

			$sql = "SELECT DISTINCT u.id, u.firstname, u.lastname, u.imagealt, u.picture, u.idnumber
					  FROM {$CFG->prefix}user u
						   JOIN {$CFG->prefix}role_assignments ra ON u.id = ra.userid
						   $this->groupsql
					 WHERE ra.roleid in ($this->gradebookroles)
						   $this->groupwheresql
						   AND ra.contextid ".get_related_contexts_string($this->context)."
				  ORDER BY $sort";
		}


		$this->users = get_records_sql($sql, $this->get_pref('studentsperpage') * $this->page,
							$this->get_pref('studentsperpage'));

		if (empty($this->users)) {
			$this->userselect = '';
			$this->users = array();
		} else {
			$this->userselect = 'AND g.userid in ('.implode(',', array_keys($this->users)).')';
		}

		return $this->users;
	}

	/**
	 * we supply the userids in this query, and get all the grades
	 * pulls out all the grades, this does not need to worry about paging
	 */
	function load_final_grades() {
		global $CFG;

		// please note that we must fetch all grade_grades fields if we want to contruct grade_grade object from it!
		$sql = "SELECT g.*
				  FROM {$CFG->prefix}grade_items gi,
					   {$CFG->prefix}grade_grades g
				 WHERE g.itemid = gi.id AND gi.courseid = {$this->courseid} {$this->userselect}";

		$userids = array_keys($this->users);


		if ($grades = get_records_sql($sql)) {
			foreach ($grades as $graderec) {
				if (in_array($graderec->userid, $userids) and array_key_exists($graderec->itemid, $this->gtree->items)) { // some items may not be present!!
					$this->grades[$graderec->userid][$graderec->itemid] = new grade_grade($graderec, false);
					$this->grades[$graderec->userid][$graderec->itemid]->grade_item =& $this->gtree->items[$graderec->itemid]; // db caching
				}
			}
		}

		// prefil grades that do not exist yet
		foreach ($userids as $userid) {
			foreach ($this->gtree->items as $itemid=>$unused) {
				if (!isset($this->grades[$userid][$itemid])) {
					$this->grades[$userid][$itemid] = new grade_grade();
					$this->grades[$userid][$itemid]->itemid = $itemid;
					$this->grades[$userid][$itemid]->userid = $userid;
					$this->grades[$userid][$itemid]->grade_item =& $this->gtree->items[$itemid]; // db caching
				}
			}
		}
	}

	/**
	 * Builds and returns a div with on/off toggles.
	 * @return string HTML code
	 */
	function get_toggles_html() {
		global $CFG, $USER, $COURSE;

		$html = '<div id="grade-report-toggles">';
		if ($USER->gradeediting[$this->courseid]) {
			if (has_capability('moodle/grade:manage', $this->context) or has_capability('moodle/grade:hide', $this->context)) {
				$html .= $this->print_toggle('eyecons', true);
			}
			if (has_capability('moodle/grade:manage', $this->context)
			 or has_capability('moodle/grade:lock', $this->context)
			 or has_capability('moodle/grade:unlock', $this->context)) {
				$html .= $this->print_toggle('locks', true);
			}
			if (has_capability('moodle/grade:manage', $this->context)) {
				$html .= $this->print_toggle('quickfeedback', true);
			}

			if (has_capability('moodle/grade:manage', $this->context)) {
				$html .= $this->print_toggle('calculations', true);
			}
		}

		if ($this->canviewhidden) {
			$html .= $this->print_toggle('averages', true);
		}

		if (has_capability('moodle/grade:viewall', $this->context)
		 and has_capability('moodle/site:accessallgroups', $this->context)
		 and ($course_has_groups = true)) { // TODO replace that last condition with proper check
			$html .= $this->print_toggle('groups', true);
		}

		$html .= $this->print_toggle('ranges', true);
		if (!empty($CFG->enableoutcomes)) {
			$html .= $this->print_toggle('nooutcomes', true);
		}
		$html .= '</div>';
		return $html;
	}

	/**
	* Shortcut function for printing the grader report toggles.
	* @param string $type The type of toggle
	* @param bool $return Whether to return the HTML string rather than printing it
	* @return void
	*/
	function print_toggle($type, $return=false) {
		global $CFG;

		$icons = array('eyecons' => 't/hide.gif',
					   'calculations' => 't/calc.gif',
					   'locks' => 't/lock.gif',
					   'averages' => 't/mean.gif',
					   'quickfeedback' => 't/feedback.gif',
					   'nooutcomes' => 't/outcomes.gif');

		$pref_name = 'grade_report_show' . $type;

		if (array_key_exists($pref_name, $CFG)) {
			$show_pref = get_user_preferences($pref_name, $CFG->$pref_name);
		} else {
			$show_pref = get_user_preferences($pref_name);
		}

		$strshow = $this->get_lang_string('show' . $type, 'grades');
		$strhide = $this->get_lang_string('hide' . $type, 'grades');

		$show_hide = 'show';
		$toggle_action = 1;

		if ($show_pref) {
			$show_hide = 'hide';
			$toggle_action = 0;
		}

		if (array_key_exists($type, $icons)) {
			$image_name = $icons[$type];
		} else {
			$image_name = "t/$type.gif";
		}

		$string = ${'str' . $show_hide};

		$img = '<img src="'.$CFG->pixpath.'/'.$image_name.'" class="iconsmall" alt="'
					  .$string.'" title="'.$string.'" />'. "\n";

		$retval = '<div class="gradertoggle">' . $img . '<a href="' . $this->baseurl . "&amp;toggle=$toggle_action&amp;toggle_type=$type\">"
			 . $string . '</a></div>';

		if ($return) {
			return $retval;
		} else {
			echo $retval;
		}
	}

	/**
	 * Builds and returns the HTML code for the headers.
	 * @return string $headerhtml
	 */
	function get_headerhtml() {
		global $CFG, $USER;

		$strsortasc   = $this->get_lang_string('sortasc', 'grades');
		$strsortdesc  = $this->get_lang_string('sortdesc', 'grades');
		$strfirstname = $this->get_lang_string('firstname');
		$strlastname  = $this->get_lang_string('lastname');
		$showuseridnumber = $this->get_pref('showuseridnumber');

		if ($this->sortitemid === 'lastname') {
			if ($this->sortorder == 'ASC') {
				$lastarrow = print_arrow('up', $strsortasc, true);
			} else {
				$lastarrow = print_arrow('down', $strsortdesc, true);
			}
		} else {
			$lastarrow = '';
		}

		if ($this->sortitemid === 'firstname') {
			if ($this->sortorder == 'ASC') {
				$firstarrow = print_arrow('up', $strsortasc, true);
			} else {
				$firstarrow = print_arrow('down', $strsortdesc, true);
			}
		} else {
			$firstarrow = '';
		}
		// Prepare Table Headers
		$headerhtml = '';

		$numrows = count($this->gtree->levels);

		$columns_to_unset = array();


		foreach ($this->gtree->levels as $key=>$row) {
			$columncount = 0;
			if ($key == 0) {
				// do not display course grade category
				// continue;
			}

			$headerhtml .= '<tr class="heading r'.$this->rowcount++.'">';

			if ($key == $numrows - 1) {
				$headerhtml .= '<th class="header c'.$columncount++.'" scope="col"><a href="'.$this->baseurl.'&amp;sortitemid=firstname">'
							. $strfirstname . '</a> '
							. $firstarrow. '/ <a href="'.$this->baseurl.'&amp;sortitemid=lastname">' . $strlastname . '</a>'. $lastarrow .'</th>';
				if ($showuseridnumber) {
					if ('idnumber' == $this->sortitemid) {
						if ($this->sortorder == 'ASC') {
							$idnumberarrow = print_arrow('up', $strsortasc, true);
						} else {
							$idnumberarrow = print_arrow('down', $strsortdesc, true);
						}
					} else {
						$idnumberarrow = '';
					}
					$headerhtml .= '<th class="header c'.$columncount++.' useridnumber" scope="col"><a href="'.$this->baseurl.'&amp;sortitemid=idnumber">'
							. get_string('idnumber') . '</a> ' . $idnumberarrow . '</th>';
				}
			 } else {
				$colspan='';
				if ($showuseridnumber) {
					$colspan = 'colspan="2" ';
				}

				$headerhtml .= '<td '.$colspan.'class="cell c'.$columncount++.' topleft">&nbsp;</td>';

				if ($showuseridnumber) {
					$columncount++;
				}
			}

			foreach ($row as $columnkey => $element) {
				$sort_link = '';
				if (isset($element['object']->id)) {
					$sort_link = $this->baseurl.'&amp;sortitemid=' . $element['object']->id;
				}

				$eid	= $element['eid'];
				$object = $element['object'];
				$type   = $element['type'];
				$categorystate = @$element['categorystate'];
				$itemmodule = null;
				$iteminstance = null;

				$columnclass = 'c' . $columncount++;
				if (!empty($element['colspan'])) {
					$colspan = 'colspan="'.$element['colspan'].'"';
					$columnclass = '';
				} else {
					$colspan = '';
				}

				if (!empty($element['depth'])) {
					$catlevel = ' catlevel'.$element['depth'];
				} else {
					$catlevel = '';
				}

// Element is a filler
				if ($type == 'filler' or $type == 'fillerfirst' or $type == 'fillerlast') {
					$headerhtml .= '<th class="'.$columnclass.' '.$type.$catlevel.'" '.$colspan.' scope="col">&nbsp;</th>';
				}
// Element is a category
				else if ($type == 'category') {
					$headerhtml .= '<th class="header '. $columnclass.' category'.$catlevel.'" '.$colspan.' scope="col">'
								. shorten_text($element['object']->get_name());
					$headerhtml .= $this->get_collapsing_icon($element);

					// Print icons
					if ($USER->gradeediting[$this->courseid]) {
						$headerhtml .= $this->get_icons($element);
					}

					$headerhtml .= '</th>';
				}
// Element is a grade_item
				else {
					$itemmodule = $element['object']->itemmodule;
					$iteminstance = $element['object']->iteminstance;

					if ($element['object']->id == $this->sortitemid) {
						if ($this->sortorder == 'ASC') {
							$arrow = $this->get_sort_arrow('up', $sort_link);
						} else {
							$arrow = $this->get_sort_arrow('down', $sort_link);
						}
					} else {
						$arrow = $this->get_sort_arrow('move', $sort_link);
					}

					$hidden = '';
					if ($element['object']->is_hidden()) {
						$hidden = ' hidden ';
					}

					$headerlink = $this->gtree->get_element_header($element, true, $this->get_pref('showactivityicons'), false);
					$headerhtml .= '<th class="header '.$columnclass.' '.$type.$catlevel.$hidden.'" scope="col" onclick="set_col(this.cellIndex)">'
								. shorten_text($headerlink) . $arrow;
					$headerhtml .= '</th>';
				}

			}

			$headerhtml .= '</tr>';
		}
		return $headerhtml;
	}

	/**
	 * Builds and return the HTML rows of the table (grades headed by student).
	 * @return string HTML
	 */
	function get_studentshtml() {
		global $CFG, $USER;

		$studentshtml = '';
		$strfeedback  = $this->get_lang_string("feedback");
		$strgrade	 = $this->get_lang_string('grade');
		$gradetabindex = 1;
		$showuserimage = $this->get_pref('showuserimage');
		$showuseridnumber = $this->get_pref('showuseridnumber');
		$numusers	  = count($this->users);

		// Preload scale objects for items with a scaleid
		$scales_list = '';
		$tabindices = array();

		foreach ($this->gtree->items as $item) {
			if (!empty($item->scaleid)) {
				$scales_list .= "$item->scaleid,";
			}

			$tabindices[$item->id]['grade'] = $gradetabindex;
			$tabindices[$item->id]['feedback'] = $gradetabindex + $numusers;
			$gradetabindex += $numusers * 2;
		}
		$scales_array = array();

		if (!empty($scales_list)) {
			$scales_list = substr($scales_list, 0, -1);
			$scales_array = get_records_list('scale', 'id', $scales_list);
		}

		$row_classes = array(' even ', ' odd ');

		$row_classes = array(' even ', ' odd ');

		foreach ($this->users as $userid => $user) {

			if ($this->canviewhidden) {
				$altered = array();
				$unknown = array();
			} else {
				$hiding_affected = grade_grade::get_hiding_affected($this->grades[$userid], $this->gtree->items);
				$altered = $hiding_affected['altered'];
				$unknown = $hiding_affected['unknown'];
				unset($hiding_affected);
			}

			$columncount = 0;
			// Student name and link
			$user_pic = null;
			if ($showuserimage) {
				$user_pic = '<div class="userpic">' . print_user_picture($user, $this->courseid, NULL, 0, true) . '</div>';
			}

			$studentshtml .= '<tr class="r'.$this->rowcount++ . $row_classes[$this->rowcount % 2] . '">'
						  .'<th class="header c'.$columncount++.' user" scope="row" onclick="set_row(this.parentNode.rowIndex);">'.$user_pic
						  .'<a href="'.$CFG->wwwroot.'/user/view.php?id='.$user->id.'&amp;course='.$this->course->id.'">'
						  .fullname($user).'</a></th>';

			if ($showuseridnumber) {
				$studentshtml .= '<th class="header c'.$columncount++.' useridnumber" onclick="set_row(this.parentNode.rowIndex);">'.
						$user->idnumber.'</th>';
			}

			foreach ($this->gtree->items as $itemid=>$unused) {
				$item =& $this->gtree->items[$itemid];
				$grade = $this->grades[$userid][$item->id];

				// Get the decimal points preference for this item
				$decimalpoints = $item->get_decimals();

				if (in_array($itemid, $unknown)) {
					$gradeval = null;
				} else if (array_key_exists($itemid, $altered)) {
					$gradeval = $altered[$itemid];
				} else {
					$gradeval = $grade->finalgrade;
				}

				// MDL-11274
				// Hide grades in the grader report if the current grader doesn't have 'moodle/grade:viewhidden'
				if (!$this->canviewhidden and $grade->is_hidden()) {
					if (!empty($CFG->grade_hiddenasdate) and $grade->get_datesubmitted() and !$item->is_category_item() and !$item->is_course_item()) {
						// the problem here is that we do not have the time when grade value was modified, 'timemodified' is general modification date for grade_grades records
						$studentshtml .= '<td class="cell c'.$columncount++.'"><span class="datesubmitted">'.userdate($grade->get_datesubmitted(),get_string('strftimedatetimeshort')).'</span></td>';
					} else {
						$studentshtml .= '<td class="cell c'.$columncount++.'">-</td>';
					}
					continue;
				}

				// emulate grade element
				$eid = $this->gtree->get_grade_eid($grade);
				$element = array('eid'=>$eid, 'object'=>$grade, 'type'=>'grade');

				$cellclasses = 'cell c'.$columncount++;
				if ($item->is_category_item()) {
					$cellclasses .= ' cat';
				}
				if ($item->is_course_item()) {
					$cellclasses .= ' course';
				}
				if ($grade->is_overridden()) {
					$cellclasses .= ' overridden';
				}

				if ($grade->is_excluded()) {
					$cellclasses .= ' excluded';
				}

				$studentshtml .= '<td class="'.$cellclasses.'">';

				if ($grade->is_excluded()) {
					$studentshtml .= get_string('excluded', 'grades') . ' ';
				}

				// Do not show any icons if no grade (no record in DB to match)
				if (!$item->needsupdate and $USER->gradeediting[$this->courseid]) {
					$studentshtml .= $this->get_icons($element);
				}

				$hidden = '';
				if ($grade->is_hidden()) {
					$hidden = ' hidden ';
				}

				$gradepass = ' gradefail ';
				if ($grade->is_passed($item)) {
					$gradepass = ' gradepass ';
				} elseif (is_null($grade->is_passed($item))) {
					$gradepass = '';
				}

				// if in editting mode, we need to print either a text box
				// or a drop down (for scales)
				// grades in item of type grade category or course are not directly editable
				if ($item->needsupdate) {
					$studentshtml .= '<span class="gradingerror'.$hidden.'">'.get_string('error').'</span>';

				} else if ($USER->gradeediting[$this->courseid]) {

					if ($item->scaleid && !empty($scales_array[$item->scaleid])) {
						$scale = $scales_array[$item->scaleid];
						$gradeval = (int)$gradeval; // scales use only integers
						$scales = explode(",", $scale->scale);
						// reindex because scale is off 1

						// MDL-12104 some previous scales might have taken up part of the array
						// so this needs to be reset
						$scaleopt = array();
						$i = 0;
						foreach ($scales as $scaleoption) {
							$i++;
							$scaleopt[$i] = $scaleoption;
						}

						if ($this->get_pref('quickgrading') and $grade->is_editable()) {
							$oldval = empty($gradeval) ? -1 : $gradeval;
							if (empty($item->outcomeid)) {
								$nogradestr = $this->get_lang_string('nograde');
							} else {
								$nogradestr = $this->get_lang_string('nooutcome', 'grades');
							}
							$studentshtml .= '<input type="hidden" name="oldgrade_'.$userid.'_'
										  .$item->id.'" value="'.$oldval.'"/>';
							$studentshtml .= choose_from_menu($scaleopt, 'grade_'.$userid.'_'.$item->id,
															  $gradeval, $nogradestr, '', '-1',
															  true, false, $tabindices[$item->id]['grade']);
						} elseif(!empty($scale)) {
							$scales = explode(",", $scale->scale);

							// invalid grade if gradeval < 1
							if ($gradeval < 1) {
								$studentshtml .= '<span class="gradevalue'.$hidden.$gradepass.'">-</span>';
							} else {
								$gradeval = (int)bounded_number($grade->grade_item->grademin, $gradeval, $grade->grade_item->grademax); //just in case somebody changes scale
								$studentshtml .= '<span class="gradevalue'.$hidden.$gradepass.'">'.$scales[$gradeval-1].'</span>';
							}
						} else {
							// no such scale, throw error?
						}

					} else if ($item->gradetype != GRADE_TYPE_TEXT) { // Value type
						if ($this->get_pref('quickgrading') and $grade->is_editable()) {
							$value = format_float($gradeval, $decimalpoints);
							$studentshtml .= '<input type="hidden" name="oldgrade_'.$userid.'_'.$item->id.'" value="'.$value.'" />';
							$studentshtml .= '<input size="6" tabindex="' . $tabindices[$item->id]['grade']
										  . '" type="text" title="'. $strgrade .'" name="grade_'
										  .$userid.'_' .$item->id.'" value="'.$value.'" />';
						} else {
							$studentshtml .= '<span class="gradevalue'.$hidden.$gradepass.'">'.format_float($gradeval, $decimalpoints).'</span>';
						}
					}


					// If quickfeedback is on, print an input element
					if ($this->get_pref('showquickfeedback') and $grade->is_editable()) {
						if ($this->get_pref('quickgrading')) {
							$studentshtml .= '<br />';
						}
						$studentshtml .= '<input type="hidden" name="oldfeedback_'
									  .$userid.'_'.$item->id.'" value="' . s($grade->feedback) . '" />';
						$studentshtml .= '<input class="quickfeedback" tabindex="' . $tabindices[$item->id]['feedback']
									  . '" size="6" title="' . $strfeedback . '" type="text" name="feedback_'
									  .$userid.'_'.$item->id.'" value="' . s($grade->feedback) . '" />';
					}

				} else { // Not editing
					$gradedisplaytype = $item->get_displaytype();

					// If feedback present, surround grade with feedback tooltip: Open span here
					if (!empty($grade->feedback)) {
						$overlib = '';
						$feedback = addslashes_js(trim(format_string($grade->feedback, $grade->feedbackformat)));
						$overlib = "return overlib('$feedback', BORDER, 0, FGCLASS, 'feedback', "
								  ."CAPTIONFONTCLASS, 'caption', CAPTION, '$strfeedback');";
						$studentshtml .= '<span onmouseover="'.s($overlib).'" onmouseout="return nd();">';
					}

					if ($item->needsupdate) {
						$studentshtml .= '<span class="gradingerror'.$hidden.$gradepass.'">'.get_string('error').'</span>';

					} else {
						$studentshtml .= '<span class="gradevalue'.$hidden.$gradepass.'">'.grade_format_gradevalue($gradeval, $item, true, $gradedisplaytype, null).'</span>';
					}

					// Close feedback span
					if (!empty($grade->feedback)) {
						$studentshtml .= '</span>';
					}
				}

				if (!empty($this->gradeserror[$item->id][$userid])) {
					$studentshtml .= $this->gradeserror[$item->id][$userid];
				}

				$studentshtml .=  '</td>' . "\n";
			}
			$studentshtml .= '</tr>';
		}
		return $studentshtml;
	}

	/**
	 * Builds and return the HTML row of column totals.
	 * @param  bool $grouponly Whether to return only group averages or all averages.
	 * @return string HTML
	 */
	function get_avghtml($grouponly=false) {
		global $CFG, $USER;

		if (!$this->canviewhidden) {
			// totals might be affected by hiding, if user can not see hidden grades the aggregations might be altered
			// better not show them at all if user can not see all hideen grades
			return;
		}

		$averagesdisplaytype   = $this->get_pref('averagesdisplaytype');
		$averagesdecimalpoints = $this->get_pref('averagesdecimalpoints');
		$meanselection		 = $this->get_pref('meanselection');
		$shownumberofgrades	= $this->get_pref('shownumberofgrades');
		$showuseridnumber	  = $this->get_pref('showuseridnumber');

		$avghtml = '';
		$avgcssclass = 'avg';

		if ($grouponly) {
			$straverage = get_string('groupavg', 'grades');
			$showaverages = $this->currentgroup && $this->get_pref('showgroups');
			$groupsql = $this->groupsql;
			$groupwheresql = $this->groupwheresql;
			$avgcssclass = 'groupavg';
		} else {
			$straverage = get_string('overallaverage', 'grades');
			$showaverages = $this->get_pref('showaverages');
			$groupsql = "";
			$groupwheresql = "";
		}

		if ($shownumberofgrades) {
			$straverage .= ' (' . get_string('submissions', 'grades') . ') ';
		}

		$totalcount = $this->get_numusers($grouponly);

		if ($showaverages) {

			// find sums of all grade items in course
			$SQL = "SELECT g.itemid, SUM(g.finalgrade) AS sum
					  FROM {$CFG->prefix}grade_items gi
						   JOIN {$CFG->prefix}grade_grades g	  ON g.itemid = gi.id
						   JOIN {$CFG->prefix}user u			  ON u.id = g.userid
						   JOIN {$CFG->prefix}role_assignments ra ON ra.userid = u.id
						   $groupsql
					 WHERE gi.courseid = $this->courseid
						   AND ra.roleid in ($this->gradebookroles)
						   AND ra.contextid ".get_related_contexts_string($this->context)."
						   AND g.finalgrade IS NOT NULL
						   $groupwheresql
				  GROUP BY g.itemid";
			$sum_array = array();
			if ($sums = get_records_sql($SQL)) {
				foreach ($sums as $itemid => $csum) {
					$sum_array[$itemid] = $csum->sum;
				}
			}

			$columncount=0;
			$colspan='';
			if ($showuseridnumber) {
				$colspan = 'colspan="2" ';
			}

			$avghtml = '<tr class="' . $avgcssclass . ' r'.$this->rowcount++.'"><th class="header c0" '.$colspan.'scope="row">'.$straverage.'</th>';

			if ($showuseridnumber) {
				$columncount++;
			}

			// MDL-10875 Empty grades must be evaluated as grademin, NOT always 0
			// This query returns a count of ungraded grades (NULL finalgrade OR no matching record in grade_grades table)
			$SQL = "SELECT gi.id, COUNT(u.id) AS count
					  FROM {$CFG->prefix}grade_items gi
						   CROSS JOIN {$CFG->prefix}user u
						   JOIN {$CFG->prefix}role_assignments ra		ON ra.userid = u.id
						   LEFT OUTER JOIN  {$CFG->prefix}grade_grades g ON (g.itemid = gi.id AND g.userid = u.id AND g.finalgrade IS NOT NULL)
						   $groupsql
					 WHERE gi.courseid = $this->courseid
						   AND ra.roleid in ($this->gradebookroles)
						   AND ra.contextid ".get_related_contexts_string($this->context)."
						   AND g.id IS NULL
						   $groupwheresql
				  GROUP BY gi.id";

			$ungraded_counts = get_records_sql($SQL);

			foreach ($this->gtree->items as $itemid=>$unused) {
				$item =& $this->gtree->items[$itemid];

				if ($item->needsupdate) {
					$avghtml .= '<td class="cell c' . $columncount++.'"><span class="gradingerror">'.get_string('error').'</span></td>';
					continue;
				}

				if (!isset($sum_array[$item->id])) {
					$sum_array[$item->id] = 0;
				}

				if (empty($ungraded_counts[$itemid])) {
					$ungraded_count = 0;
				} else {
					$ungraded_count = $ungraded_counts[$itemid]->count;
				}

				if ($meanselection == GRADE_REPORT_MEAN_GRADED) {
					$mean_count = $totalcount - $ungraded_count;
				} else { // Bump up the sum by the number of ungraded items * grademin
					$sum_array[$item->id] += $ungraded_count * $item->grademin;
					$mean_count = $totalcount;
				}

				$decimalpoints = $item->get_decimals();

				// Determine which display type to use for this average
				if ($USER->gradeediting[$this->courseid]) {
					$displaytype = GRADE_DISPLAY_TYPE_REAL;

				} else if ($averagesdisplaytype == GRADE_REPORT_PREFERENCE_INHERIT) { // no ==0 here, please resave the report and user preferences
					$displaytype = $item->get_displaytype();

				} else {
					$displaytype = $averagesdisplaytype;
				}

				// Override grade_item setting if a display preference (not inherit) was set for the averages
				if ($averagesdecimalpoints == GRADE_REPORT_PREFERENCE_INHERIT) {
					$decimalpoints = $item->get_decimals();

				} else {
					$decimalpoints = $averagesdecimalpoints;
				}

				if (!isset($sum_array[$item->id]) || $mean_count == 0) {
					$avghtml .= '<td class="cell c' . $columncount++.'">-</td>';
				} else {
					$sum = $sum_array[$item->id];
					$avgradeval = $sum/$mean_count;
					$gradehtml = grade_format_gradevalue($avgradeval, $item, true, $displaytype, $decimalpoints);

					$numberofgrades = '';
					if ($shownumberofgrades) {
						$numberofgrades = " ($mean_count)";
					}

					$avghtml .= '<td class="cell c' . $columncount++.'">'.$gradehtml.$numberofgrades.'</td>';
				}
			}
			$avghtml .= '</tr>';
		}
		return $avghtml;
	}

	/**
	 * Builds and return the HTML row of ranges for each column (i.e. range).
	 * @return string HTML
	 */
	function get_rangehtml() {
		global $USER;
		$showuseridnumber	  = $this->get_pref('showuseridnumber');

		$scalehtml = '';
		if ($this->get_pref('showranges')) {
			$rangesdisplaytype   = $this->get_pref('rangesdisplaytype');
			$rangesdecimalpoints = $this->get_pref('rangesdecimalpoints');

			$columncount=0;
			$colspan='';
			if ($showuseridnumber) {
				$colspan = 'colspan="2" ';
			}

			$scalehtml = '<tr class="r'.$this->rowcount++.'">'
					   . '<th class="header c0 range" '.$colspan.'scope="row">'.$this->get_lang_string('range','grades').'</th>';

			if ($showuseridnumber) {
				$columncount++;
			}

			foreach ($this->gtree->items as $itemid=>$unused) {
				$item =& $this->gtree->items[$itemid];


				$hidden = '';
				if ($item->is_hidden()) {
					$hidden = ' hidden ';
				}

				$formatted_range = $item->get_formatted_range($rangesdisplaytype, $rangesdecimalpoints);

				$scalehtml .= '<th class="header c'.$columncount++.' range"><span class="rangevalues'.$hidden.'">'. $formatted_range .'</span></th>';

			}
			$scalehtml .= '</tr>';
		}
		return $scalehtml;
	}

	/**
	 * Builds and return the HTML row of ranges for each column (i.e. range).
	 * @return string HTML
	 */
	function get_iconshtml() {
		global $USER;

		$iconshtml = '';
		if ($USER->gradeediting[$this->courseid]) {

			$colspan='';
			if ($this->get_pref('showuseridnumber')) {
				$colspan = 'colspan="2" ';
			}

			$iconshtml = '<tr class="r'.$this->rowcount++.'">'
					   . '<th class="header c0 range" scope="row" '.$colspan.'>'.$this->get_lang_string('controls','grades').'</th>';

			$columncount = 1;
			foreach ($this->gtree->items as $itemid=>$unused) {
				// emulate grade element
				$item =& $this->gtree->items[$itemid];

				$eid = $this->gtree->get_item_eid($item);
				$element = $this->gtree->locate_element($eid);

				$iconshtml .= '<td class="cell c'.$columncount++.' icons">' . $this->get_icons($element) . '</td>';
			}
			$iconshtml .= '</tr>';
		}
		return $iconshtml;
	}

	/**
	 * Given a grade_category, grade_item or grade_grade, this function
	 * figures out the state of the object and builds then returns a div
	 * with the icons needed for the grader report.
	 *
	 * @param object $object
	 * @return string HTML
	 */
	function get_icons($element) {
		global $CFG, $USER;

		if (!$USER->gradeediting[$this->courseid]) {
			return '<div class="grade_icons" />';
		}

		// Init all icons
		$edit_icon			 = $this->gtree->get_edit_icon($element, $this->gpr);
		$edit_calculation_icon = '';
		$show_hide_icon		= '';
		$lock_unlock_icon	  = '';

		if (has_capability('moodle/grade:manage', $this->context)) {

			if ($this->get_pref('showcalculations')) {
				$edit_calculation_icon = $this->gtree->get_calculation_icon($element, $this->gpr);
			}

			if ($this->get_pref('showeyecons')) {
			   $show_hide_icon = $this->gtree->get_hiding_icon($element, $this->gpr);
			}

			if ($this->get_pref('showlocks')) {
				$lock_unlock_icon = $this->gtree->get_locking_icon($element, $this->gpr);
			}
		}

		return '<div class="grade_icons">'.$edit_icon.$edit_calculation_icon.$show_hide_icon.$lock_unlock_icon.'</div>';
	}

	/**
	 * Given a category element returns collapsing +/- icon if available
	 * @param object $object
	 * @return string HTML
	 */
	function get_collapsing_icon($element) {
		global $CFG;

		$contract_expand_icon = '';
		// If object is a category, display expand/contract icon
		if ($element['type'] == 'category') {
			// Load language strings
			$strswitch_minus = $this->get_lang_string('aggregatesonly', 'grades');
			$strswitch_plus  = $this->get_lang_string('gradesonly', 'grades');
			$strswitch_whole = $this->get_lang_string('fullmode', 'grades');

			$expand_contract = 'switch_minus'; // Default: expanded
			// $this->get_pref('aggregationview', $element['object']->id) == GRADE_REPORT_AGGREGATION_VIEW_COMPACT

			if (in_array($element['object']->id, $this->collapsed['aggregatesonly'])) {
				$expand_contract = 'switch_plus';
			} elseif (in_array($element['object']->id, $this->collapsed['gradesonly'])) {
				$expand_contract = 'switch_whole';
			}
			$url = $this->gpr->get_return_url(null, array('target'=>$element['eid'], 'action'=>$expand_contract, 'sesskey'=>sesskey()));
			$contract_expand_icon = '<a href="'.$url.'"><img src="'.$CFG->pixpath.'/t/'.$expand_contract.'.gif" class="iconsmall" alt="'
									.${'str'.$expand_contract}.'" title="'.${'str'.$expand_contract}.'" /></a>';
		}
		return $contract_expand_icon;
	}

	/**
	 * Processes a single action against a category, grade_item or grade.
	 * @param string $target eid ({type}{id}, e.g. c4 for category4)
	 * @param string $action Which action to take (edit, delete etc...)
	 * @return
	 */
	function process_action($target, $action) {
		// TODO: this code should be in some grade_tree static method
		$targettype = substr($target, 0, 1);
		$targetid = substr($target, 1);
		// TODO: end

		if ($collapsed = get_user_preferences('grade_report_grader_collapsed_categories')) {
			$collapsed = unserialize($collapsed);
		} else {
			$collapsed = array('aggregatesonly' => array(), 'gradesonly' => array());
		}

		switch ($action) {
			case 'switch_minus': // Add category to array of aggregatesonly
				if (!in_array($targetid, $collapsed['aggregatesonly'])) {
					$collapsed['aggregatesonly'][] = $targetid;
					set_user_preference('grade_report_grader_collapsed_categories', serialize($collapsed));
				}
				break;

			case 'switch_plus': // Remove category from array of aggregatesonly, and add it to array of gradesonly
				$key = array_search($targetid, $collapsed['aggregatesonly']);
				if ($key !== false) {
					unset($collapsed['aggregatesonly'][$key]);
				}
				if (!in_array($targetid, $collapsed['gradesonly'])) {
					$collapsed['gradesonly'][] = $targetid;
				}
				set_user_preference('grade_report_grader_collapsed_categories', serialize($collapsed));
				break;
			case 'switch_whole': // Remove the category from the array of collapsed cats
				$key = array_search($targetid, $collapsed['gradesonly']);
				if ($key !== false) {
					unset($collapsed['gradesonly'][$key]);
					set_user_preference('grade_report_grader_collapsed_categories', serialize($collapsed));
				}

				break;
			default:
				break;
		}

		return true;
	}
}
?>
